I needed to add a circuit to my Murray 200A panel. The panel was installed 10 years ago.
I purchased a Murray twin breaker from Lowes, and I installed in the panel with no problem.

Then I did some reading that most 40 ckt panels will not accept a twin breaker. And then I read the inside label of my panel, it did not indicate any twin breakers could be used

So now I'm confused. How was this twin breaker able to be installed? I thought these panels had provisions or interlocks that prevented these breakers form being installed?

On Sunday, September 28, 2014 9:18:10 AM UTC-4, Mikepier wrote:
I needed to add a circuit to my Murray 200A panel. The panel was installed 10 years ago.

I purchased a Murray twin breaker from Lowes, and I installed in the panel with no problem.



Then I did some reading that most 40 ckt panels will not accept a twin breaker. And then I read the inside label of my panel, it did not indicate any twin breakers could be used



So now I'm confused. How was this twin breaker able to be installed? I thought these panels had provisions or interlocks that prevented these breakers form being installed?

lets see you needed a breaker installed a twin and it works?

then dont worry about it

"bob haller"

So now I'm confused. How was this twin breaker
able to be installed? I thought these panels
had provisions or interlocks that prevented
these breakers form being installed?

lets see, you needed a breaker, installed a
twin, and it works?

then dont worry about it

Sounds to me like a dumb-assed con-artist ins.co.
thief
said 'you can't do that, it might cost us money' !

"Mikepier" wrote in message
...
I needed to add a circuit to my Murray 200A panel. The panel was installed
10 years ago.
I purchased a Murray twin breaker from Lowes, and I installed in the
panel with no problem.

Then I did some reading that most 40 ckt panels will not accept a twin
breaker. And then I read the inside label of my panel, it did not
indicate any twin breakers could be used

So now I'm confused. How was this twin breaker able to be installed? I
thought these panels had provisions or interlocks that prevented these
breakers form being installed?

I thought I was going to make a quick paraphrasing effort and look
brilliant, but just read this yourself!


http://www.structuretech1.com/2012/0...cuit-breakers/

On 09/28/2014 9:15 AM, Pico Rico wrote:
....

I thought I was going to make a quick paraphrasing effort and look
brilliant, but just read this yourself!


http://www.structuretech1.com/2012/0...cuit-breakers/

Nice link, thanks! Wasn't aware of the recent changes in NEC in this area.

BTW, I've never seen the Square D horizontally-spaced tandem style...

--

On 9/28/2014 10:15 AM, Pico Rico wrote:
I thought I was going to make a quick paraphrasing effort and look
brilliant, but just read this yourself!


http://www.structuretech1.com/2012/0...cuit-breakers/



Thank you. I learned a lot.


..
Christopher A. Young
Learn about Jesus
www.lds.org
..

Thanks for the article. So if I'm reading it correctly, tandem breakers can be used in non-CTL panels?

How do I know if my Murray 200A panel is non-CTL? I don't see anywhere on the label. The model number is LC4040B1200. Attached is the label.

http://www.homedepot.com/catalog/pdf...055abf9d39.pdf

On 09/28/2014 5:25 PM, Mikepier wrote:
Thanks for the article. So if I'm reading it correctly, tandem
breakers can be used in non-CTL panels?

If the panel indicates so, yes, in those locations.

How do I know if my Murray 200A panel is non-CTL? I don't see
anywhere on the label. The model number is LC4040B1200. Attached is the label.
....

If it doesn't say it is, it isn't...

And, the pictures at the top indicate it doesn't allow _any_ tandem
breakers (they're no double lines in any locations). See how the
samples in the previous link show where they are/aren't allowed...

--

On Sunday, September 28, 2014 7:21:11 PM UTC-4, dpb wrote:
On 09/28/2014 5:25 PM, Mikepier wrote:

Thanks for the article. So if I'm reading it correctly, tandem

breakers can be used in non-CTL panels?



If the panel indicates so, yes, in those locations.



How do I know if my Murray 200A panel is non-CTL? I don't see

anywhere on the label. The model number is LC4040B1200. Attached is the label.

...



If it doesn't say it is, it isn't...



And, the pictures at the top indicate it doesn't allow _any_ tandem

breakers (they're no double lines in any locations). See how the

samples in the previous link show where they are/aren't allowed...



--

Confusing to say the least. Even though its not shown on the label, I thought the article says something to the effect that if the panel is not CTL rated ( which it does not appear to be because I do not see anything on the label saying "MAX circuits 42'), then I was under the assumption it could be used.

Unfortunately that panel label seems to preclude your tandem breaker.



The type "MT" (tandem) is not on the list of approved breaker types.

It probably won't burn your house down but it is not legal.

That would appear to be the case. Ok no big deal. I actually used a twin breaker to re-arrange some breakers in my panel to accommodate putting a 30A backfed generator inlet on the top right.

I actually have plenty of spaces left in my panel, but one of the 15A circuits in the panel would not reach to the new spot of the breaker, so to avoid extending it with another wire and wire nut, I just used a twin.

In ,
Mikepier typed:
typed:
Unfortunately that panel label seems to preclude your tandem breaker.

The type "MT" (tandem) is not on the list of approved breaker types.

It probably won't burn your house down but it is not legal.

That would appear to be the case. Ok no big deal. I actually used a
twin breaker to re-arrange some breakers in my panel to accommodate
putting a 30A backfed generator inlet on the top right.

I actually have plenty of spaces left in my panel, but one of the 15A
circuits in the panel would not reach to the new spot of the breaker,
so to avoid extending it with another wire and wire nut, I just used
a twin.

Interesting thread. I never knew that there technically could be a legal or
other issue when using a tandem breaker in a panel. I just assumed that if
it fit in the slot and it worked, it was okay to use.

But, since you have plenty of extra spaces, and you can put in a regular
breaker by just using a wire nut inside the panel extending the existing
wire, I think that I would have chosen that option rather than buying and
putting in a tandem breaker. That would eliminate the whole question or
issue of whether using a tandem breaker in that panel is proper or legal
etc.

On Sunday, September 28, 2014 6:25:50 PM UTC-4, Mikepier wrote:
Thanks for the article. So if I'm reading it correctly, tandem breakers can be used in non-CTL panels?



How do I know if my Murray 200A panel is non-CTL? I don't see anywhere on the label. The model number is LC4040B1200. Attached is the label.



http://www.homedepot.com/catalog/pdf...055abf9d39.pdf



*The catalog number says it all. 40 spaces, 40 circuits, period. One thing that I noticed on that label is the notation indicating the location where a backfed circuit breaker must go in slots #1 and #3. This may limit the use of third party generator interlock kits which tend to be located in the #2 and #4 slots. Most likely Murray (Siemens) has their own interlock kit for this panel. Just an observation. Sorry to digress.

John Grabowski
http://www.MrElectrician.TV